package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {
    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IFollowService followService;

    /**
     * 查询热点博客，分页展示
     * @param current
     * @return
     */
    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog -> {
            this.queryBlog(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }



    /**
     * 根据博客id查询博客信息
     * @param id
     * @return
     */
    @Override
    public Result queryBlogById(Long id) {
        Blog blog = getById(id);
        if (blog == null){
            return Result.fail("笔记不存在!");
        }
        blog = queryBlog(blog);
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    @Override
    public Result likeBlog(Long id) {
        String key = RedisConstants.BLOG_LIKED_KEY + id;
        //判断当前用户是否是否点过赞
        Long userId = UserHolder.getUser().getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if (score == null){
            //没点过赞
            //修改点赞量
            boolean success = update().setSql("liked = liked + 1").eq("id", id).update();
            if (success){
                //向redis中增加
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }else{
            //点过赞了
            //修改点赞量
            boolean success = update().setSql("liked = liked - 1").eq("id", id).update();
            if (success){
                //从redis中删除
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }
        return Result.ok();
    }

    /**
     * 查询博客的点赞列表，返回前五个点赞的用户信息
     * @param id
     * @return
     */
    @Override
    public Result queryBlogLikes(Long id) {
        String key = RedisConstants.BLOG_LIKED_KEY + id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idsSrt = StrUtil.join(",", ids);
        List<UserDTO> userDTOS = userService.query().
                in("id",ids).last("order by field(id," +idsSrt + ")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        return Result.ok(userDTOS);
    }

    @Override
    public Result saveBlog(Blog blog) {
        // 获取登录用户
        Long userId = UserHolder.getUser().getId();
        blog.setUserId(userId);
        // 保存探店博文
        boolean isSuccess = save(blog);
        if (!isSuccess){
            return Result.fail("新增笔记失败！");
        }
        //获取博主的所有粉丝
        List<Follow> users = followService.query().eq("follow_user_id", userId).list();
        for (Follow user : users) {
            //给所有的粉丝推送
            Long id = user.getUserId();
            String key = RedisConstants.FEED_KEY + id;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }
        // 返回id
        return Result.ok(blog.getId());
    }

    /**
     * 分页查询推送的关注信息
     * @param max
     * @param offset
     * @return
     */
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //获取当前的用户的收件箱
        Long userId = UserHolder.getUser().getId();
        String key = RedisConstants.FEED_KEY + userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        if (typedTuples == null || typedTuples.isEmpty()){
            return Result.ok();
        }
        //解析得到的数据,需要获取博客id集合、最小时间（下一次查询的max）、下一次需要的偏移量
        List<Long> blogIdList = new ArrayList<>(typedTuples.size());
        int os =  1;
        long minTime = 0;
        for (ZSetOperations.TypedTuple<String> typedTuple : typedTuples) {
            blogIdList.add(Long.valueOf(typedTuple.getValue()));
            long time = typedTuple.getScore().longValue();
            if (time == minTime) {
                os ++;
            }else{
                os = 1;
                minTime = time;
            }
        }
        os = minTime == max ? os : os + offset;
        //查询具体博客数据
        String ids = StrUtil.join(",", blogIdList);
        List<Blog> blogList = query().in("id", blogIdList).last("order by field(id," + ids + ")").list();
        //设置博客中用户的信息和当前用户的点赞状态
        for (Blog blog : blogList) {
            blog = queryBlog(blog);
            isBlogLiked(blog);
        }
        //封装返回
        ScrollResult scrollResult = new ScrollResult();
        scrollResult.setList(blogList);
        scrollResult.setMinTime(minTime);
        scrollResult.setOffset(os);
        return Result.ok(scrollResult);
    }

    /**
     * 设置isLiked的状态值
     * @param blog
     */
    private void isBlogLiked(Blog blog){
        String key = RedisConstants.BLOG_LIKED_KEY + blog.getId();
        UserDTO userDTO = UserHolder.getUser();
        if (userDTO == null){
            log.info("用户未登录！");
            return ;
        }
        //判断当前用户是否是否点过赞
        Long userId =userDTO.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }

    /**
     * 公共方法
     * @param blog
     * @return
     */
    private Blog queryBlog(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
        return blog;
    }
}
